The primary objective is to determine whether fast neutron theraphy is superior to the best current treatment methods in the management of locally advanced malignant tumors. To achieve this goal, cooperative clinical trials have been initiated under the direction of the Radiation Therapy Oncology Group. The majority of these trials are randomized studies comparing neutron therapy with ceonventional treatment by surgery, photon irradiation, or combined surgery and photon irradiation. In addition to a continuation of the clinical trial in human cancer, research in physics and radiobiology will be carried out in order to (1) improve neutron treatment techniques and dosage schedules, (2) evaluate acute and late effects on normal tissues, (3) explore the potential for combinations with other treatment modalities, and (4) define a patient population for future clinical trials. Between 1972 and 1980, the M.D. Anderson neutron therapy program used the 50MeV(d Be) TAMVEC cyclotron located at Texas A&M University, 100 miles from Houston. The program is now being transferred to M. D. Anderson Hospital where a 42MeV(p BE) cyclotron specifically designed for neutron therapy and cancer research is being installed.